Single-cell sequencing further identified CCR7 as the main surface marker of a malignant T cell subpopulation, indicating that CCR7 is a key chemotactic factor receptor that mediates lymphocyte homing and migration and, thus, —may play an important role in the disease regulation of CTCL [34]. The gene discussed is CCR7; the disease is primary cutaneous T-cell non-Hodgkin lymphoma.